ContextRosai-Dorfman disease is a rare histiocytic disorder that primarily affects lymph nodes but may present at extranodal sites. Breast involvement is exceptionally rare and often mimics malignancy on clinical and imaging studies, leading to diagnostic challenges.ObjectiveTo describe the clinical, radiologic, and pathologic features of breast Rosai-Dorfman disease and review management outcomes.DesignWe retrospectively reviewed all instances of breast Rosai-Dorfman disease diagnosed at our institution over a 14-month period. Clinical records, imaging studies, histopathology, treatment, and follow-up data were analyzed.ResultsA total of three patients were diagnosed with Rosai-Dorfman disease of the breast. All three patients were women aged 22 to 71 years. Two presented with palpable breast masses, and one patient had a mass that was incidentally detected on chest computed tomography. Imaging demonstrated irregular masses categorized as Breast Imaging Reporting and Data System (BI-RADS) category 4-5, suspicious for carcinoma. Histopathologic examination showed dense lymphoplasmacytic infiltrates with histiocytes exhibiting emperipolesis and immunoreactivity for S100, CD68, and CD163, with negative CD1A staining. Two patients underwent excision, and one was managed conservatively. At follow-up, all patients remained disease-free without recurrence or systemic involvement.ConclusionsBreast Rosai-Dorfman disease is a rare benign entity that closely mimics carcinoma both clinically and radiologically. Accurate diagnosis relies on histopathologic evaluation with immunohistochemistry. Management may range from observation to surgical excision depending on lesion size and symptoms. Awareness of this presentation is essential to prevent misdiagnosis and overtreatment.
Guzman et al. (2026) studied this question.